JP2737023B2 - Vibration type scratch tester - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type scratch tester for measuring mechanical properties of a solid surface or a thin film formed on the solid surface.

[Prior art] To improve the quality of a thin film on a solid surface formed by various thin film forming means such as vacuum deposition, sputtering, and ion plating, it is important to accurately measure the adhesion of the thin film to a substrate. Has become a major challenge.

Conventionally, as a means for measuring the adhesion of a thin film,
A device according to 140 939 is known. This device will be described with reference to FIG.

This apparatus includes a vibrating device 102, a contact needle 110 vibrated by the vibrating device 102, and a sample table 112. During a test, a sample 111 is placed on the sample table 112, and the contact needle 110 is After being brought into contact with the sample surface, the contact needle 110 is vibrated at a low frequency.
Then, a vibration output corresponding to a frictional force generated between the contact needle 110 and the sample surface during that time is detected, and the dynamic characteristics are measured based on the magnitude and waveform of the detected output and its change. Hereinafter, such a device is referred to as a horizontal vibration type scratch tester.

In this tester, in order to determine the adhesion of the thin film to the substrate, it is essential to measure the load applied to the thin film by the contact needle 110, and the measurement accuracy of this load determines the measurement accuracy of this adhesion. I do.

[Problems to be Solved by the Invention] However, in such a conventional technique, there is no effective means for measuring the load of the contact needle applied to the sample, and thus the measurement accuracy is not sufficient.

An object of the present invention is to provide an effective means for measuring the load applied to a sample by a contact needle in a vibration-type scratch tester in view of the problems of the related art, and improve the measurement accuracy of the tester. To make it happen.

Another object of the present invention is to enable measurement of a non-flat test surface in such a testing machine.

[Means for Solving the Problems] In order to achieve the above object, a vibration-type scratch tester of the present invention includes a contact needle that contacts a sample, and holds the contact needle. An elastic lever member that applies a force whose displacement is temporally variable to the contact needle to contact the contact needle with the sample, and moves the sample in a predetermined direction along the sample surface relative to the elastic lever member. Moving means for moving, vibrating means for holding the elastic lever member and vibrating in a direction along a sample surface perpendicular to the moving direction of the moving means, and torsion detecting a torsion state of the elastic lever member State detecting means; and a displacement amount detecting means for detecting a displacement amount of the contact needle held by the elastic lever member in a direction substantially perpendicular to the sample surface.

The displacement detecting means includes, for example, a reflecting mirror whose position is fixed with respect to the contact needle, and an optical displacement meter probe for receiving light reflected by the reflecting mirror and detecting displacement of the contact needle. Optical detection means, an installation electrode whose position is fixed with respect to the contact needle, and an electrostatic capacitance measurement probe for detecting the capacitance by pairing with the storage electrode and storing the charge. Alternatively, a capacitance type can be used.

[Operation] In this configuration, when the elastic body lever member is vibrated and the contact needle is brought into contact with the sample and the sample is moved in a predetermined direction so that the position of the contact needle in the sample direction is reduced, the contact on the sample surface occurs. The force applied by the needle increases, and the amount of torsion of the elastic lever member due to the frictional force between the sample surface and the contact needle (the maximum displacement in the vibration direction during one-time vibration of the lever member or one-way movement of the lever member) Increases at a substantially constant rate with respect to the displacement of the contact needle in the direction of the sample. When the force applied by the contact needle onto the sample surface exceeds a certain value, a change occurs on the sample surface such as peeling of the coating on the sample surface, and the frictional force between the sample surface and the contact needle is reduced. Abruptly changing, the amount of twist of the elastic lever member also fluctuates irregularly. The force applied by the contact needle onto the sample surface at this time is accurately determined from the elastic modulus of the elastic lever member and the amount of displacement of the contact needle in a direction substantially perpendicular to the sample surface. The mechanical properties of the sample surface such as the adhesion strength of the sample can be obtained.

According to this, the displacement of the contact needle in a direction substantially perpendicular to the sample surface is directly and accurately measured, and the load of the contact needle when the sample surface changes is accurately determined. Therefore, even when the sample surface is not a flat surface such as a concave surface or a convex surface. The mechanical properties of the sample surface can be accurately obtained.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view showing a horizontal vibration type scratch tester according to one embodiment of the present invention. In the figure, the elastic lever 109 is fixed to the piezoelectric element 107, and the elastic lever 10
A contact needle 110 extending downward is fixed to the lower end of the tip 9 and a reflecting mirror 108 facing upward is fixed to the upper end of the tip.
The vibration device mounting base 101 is fixed to a test machine main body (not shown), and a vibration device 102 is mounted on the vibration device mounting table 101. The vibration device 102 is oscillated by the oscillator 103 at a low frequency in the X-axis direction. The piezoelectric element 107 to which the elastic lever 109 is fixed is fixed to the vibration device 102. When the elastic body lever 109 is displaced in the X-axis direction due to a load in the X-axis direction, the piezoelectric element 107 generates a potential, and this potential is amplified by the amplifier 105 electrically connected to the piezoelectric element 107. Almost directly above the reflector 108, an optical displacement meter probe 1
06 is installed. The optical displacement meter probe 106 is electrically connected to the optical displacement meter 104.

On the other hand, the sample 111 is fixedly mounted on the XYZ axis fine movement device 112 below the contact needle 110 by a fixing mechanism (not shown). The XYZ axis fine movement device 112 is capable of fine movement in the X, Y and Z axis directions shown in the figure, and can freely set the positional relationship between the sample 111 and the contact needle 110. Further, it can move at a desired speed in the Y-axis direction. Furthermore, it is rotatable in the θ direction.

Next, a method for measuring the adhesion of the thin film on the sample surface using this apparatus will be described.

First, the position of the contact needle 110 is adjusted so that the contact needle 110 faces the sample 111 at an appropriate distance at the measurement point on the sample surface. Further, the sample surface is slightly tilted from a position perpendicular to the longitudinal direction of the contact needle 110, and the sample is rotated in the θ direction so that the sample surface rises to the right in the figure. Then, the vibration device 102 is vibrated at a low frequency in the X-axis direction, and the contact needle 110 is vibrated at a low frequency in the X-axis direction on the sample surface. Then, along with the low-frequency vibration, the sample 111 is moved at a constant speed in the minus Y direction (left side of the drawing). As the sample 111 moves in the Y direction, the surface of the sample in contact with the contact needle 110 is directed in the Z-axis direction (upward on the paper), and the elastic lever 109 is also displaced in the same direction. The amount of displacement at this time is an optical displacement meter 10
4 detects the change in the distance between the reflecting mirror 108 and the optical displacement meter probe 106. The load applied to the thin film on the sample surface by the contact needle 110 is the displacement amount and the elastic lever.
Obtained from 109 spring constants.

At this time, if the load on the thin film is small,
The 102 and the elastic lever 109 vibrate integrally in the X-axis direction. However, the load applied to the thin film on the sample surface increases with the movement of the sample 111, so that the frictional force between the contact needle 110 and the thin film on the sample surface increases. Then, since the vibration of the elastic body lever 109 does not follow the vibration of the vibration device 102, a torsional displacement occurs between the elastic body lever 109 and the piezoelectric element 107. This torsional displacement is detected by the amplifier 105.

Here, the torsional displacement increases as the load increases, but when the load reaches a certain value, the torsional displacement rapidly changes. This is because the frictional force is changed to the frictional force of the substrate when the thin film of the portion in contact with the contact needle 110 is broken. Therefore, the adhesive force of the thin film can be measured based on the load at the place where the torsional displacement has drastically changed.

FIG. 2 is a schematic view showing a horizontal vibration type scratch tester according to another embodiment of the present invention.

The difference from the above-described embodiment is that a ground electrode 208 and a capacitance measuring probe 206 are provided in place of the reflecting mirror 108 and the optical displacement meter probe 106, and the distance between them is measured. Amplifier 204b via bridge 204a
This distance is detected as a change in the current value. Other operations are the same as those in the above embodiment.

Next, an example in which the adhesion of the deposited film on the glass surface is measured using the tester shown in FIG. 1 will be described.

 The measured samples are the following three types a to c.

Sample a: A MgF ₂ thin film was formed on a lens (material: BK-7) having a flat surface on one side and a convex surface with a radius of curvature of 10 mm by vacuum evaporation. Substrate temperature for thin film formation is 30
The temperature was 0 ° C., and the thickness of the formed thin film was 1000 °.

Sample b: A film formed on a lens having a flat surface on one side and a concave surface with a radius of curvature of 10 mm on the other side under the same conditions as described above.

Sample c: A film was formed on a BK-7 (30 mm diameter) plate material having flat surfaces on both sides under the same conditions as above.

The contact needle is made of diamond and has a tip radius of 15μ.
m. As the elastic lever, a lever having a relationship between the displacement in the Z direction and the load linearly showing a displacement of 1 μm with respect to a load of 0.1 gram was used. As for the scratch speed, the moving speed of the sample in the minus Y direction was 8 μm / sec. The horizontal vibration frequency of the elastic lever was 30 Hz.

At the time of measurement, first, the sample a is placed on the XYZ fine movement moving device of the testing machine such that the flat surface faces down. However, the inclination θ of the XYZ fine movement moving device is θ = 0 °. Then, after adjusting the position of the XYZ fine movement moving device, the sample a is moved at a constant speed in the minus Y direction. At this time, the load detected by the optical displacement meter corresponding to the upward displacement of the contact needle is set on the X-axis, and the relative value of the gain obtained from the amplifier is continuously plotted on the Y-axis. In other words, the breaking point of the thin film on the sample surface is determined.

In the same manner, for the sample b and the sample c, a drastic change point of the gain is obtained. However, for sample c, θ = 2 °.

The graph obtained by superimposing the graphs of the load-amplifier relative values for the samples a to c obtained in this manner is the fourth.
FIG. Figure shows the results for each curve S _a to S _c samples a to c.

According to this, it can be seen that under the same material and under the same film forming conditions, even if the sample surface shape is different, the adhesion of the film can be measured with good reproducibility.

In the embodiment, the displacement of the elastic lever caused by the frictional force between the contact needle and the sample surface is detected by the piezoelectric element. However, the present invention is not limited to this method. Any method can be used as long as it is a means capable of detecting the stake with high sensitivity. As another method, for example, a method may be used in which a magnetic material is provided on a lever, such as a record player cartridge, and the displacement is detected by a coil.

Next, as a comparative example, all conditions were the same as in the above-mentioned embodiment except that the load applied to the contact needle was used in the following manner, and the same sample was gained using the conventional apparatus shown in FIG. Sought a place of sudden change.

That is, here, the θ of the XYZ fine movement device is set to 2 °, and the sample surface is regarded as approximately flat, so that the sample surface itself is also regarded as θ = 2 °. The load applied to the contact needle is determined by calculating the amount by which the sample has moved in the Z direction from the amount by which the sample has moved in the minus Y direction, and further multiplying this by a spring constant.

FIG. 5 is a graph of the load-amplifier gain relative value thus obtained.

According to this, it can be seen that even under the same material and the same film forming condition, the adhesion of the film cannot be measured with good reproducibility with different sample surface shapes.

[Effects of the Invention] As described above, in the vibration-type scratch tester, the displacement of the contact needle in the sample direction is detected, and the load applied to the contact needle is determined based on the displacement. The adhesion of the thin film can be accurately measured.

Similarly, measurement can be performed with high accuracy on a thin film on a surface other than a flat surface such as a convex lens.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a horizontal vibration type scratch tester using an optical displacement meter according to one embodiment of the present invention. FIG. 2 is a front view showing another embodiment of the present invention. FIG. 3 is a front view showing a configuration of a horizontal vibration type scratch tester according to the related art, which is a horizontal vibration type scratch tester and a configuration of a tester using a capacitance bridge; FIG. 4 is a graph showing the breaking point of the thin film on the sample surface obtained by the tester shown in FIG. 1, and FIG. 5 is a comparative example showing the breaking point of the thin film on the sample surface using the conventional load measuring method. FIG. 101: Vibration device mounting base, 102: Vibration device, 103: Oscillator, 104: Optical displacement meter, 105: Amplifier, 106: Optical displacement meter probe, 107: Piezoelectric element, 108: Reflecting mirror, 109: Elastic lever, 110: contact needle, 111: sample, 112: XYZ axis fine movement device, 204a: capacitance bridge, 204b: amplifier, 206: capacitance measurement probe, 208: ground electrode, 301: oscilloscope, 312: Sample table.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Tachikawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-3-87637 (JP, A)

Claims (3)

(57) [Claims] 1. A contact needle for contacting a sample, the contact needle being held by the contact needle, and a force that makes a displacement of the contact needle in a direction perpendicular to a sample surface temporally variable is applied to the contact needle to contact the sample. An elastic lever member for bringing the needle into contact, moving means for moving the sample in a predetermined direction along the sample surface relative to the elastic lever member, and movement by the moving means while holding the elastic lever member Vibrating means for vibrating in a direction along a sample surface perpendicular to the direction, torsion state detecting means for detecting a torsion state of the elastic lever member, and a sample surface of a contact needle held by the elastic lever member. A vibration type scratch tester comprising: a displacement amount detecting means for detecting a displacement amount in a substantially vertical direction. 2. A displacement amount detecting means, comprising: a reflecting mirror fixed in position with respect to the contact needle; and a probe for an optical displacement meter for detecting a displacement of the contact needle by receiving light reflected by the reflecting mirror. The vibration-type scratch tester according to claim 1, comprising: 3. The displacement amount detecting means includes an installation electrode whose position is fixed with respect to the contact needle, an electrostatic capacitance measuring probe for accumulating electric charge in pair with the installation electrode, and detecting the capacitance. The vibration-type scratch tester according to claim 1, further comprising: